Aspect Ratio's

[peppi_le_piou]

I want to rip a dvd I have. My question is to do with Aspect Ratio's which I have read a lot about but remains confusing. It will only make sense with some practical use I hope.

My dvd cover shows that it is "16:9 widescreen" and "2.35:1 letterbox". Using PowerDVD it plays with black bars top/bottom. (ps...shouldn't it be printed as "2.35:1" and "16:9 letterbox" or don't I understand it correctly)?

I run the vob through GSpot and it is 720x576; 1.25 SAR; 1.422 PAR; 1.778 DAR.

GSpot has a Resizing function that suggests to resize to 787x432 when converting to avi. That would give a DAR of 1.82 if I'm not mistaken.

When I convert the rip to avi with my program and putting in this suggested frame size the result is a 1.82 video but it contains top and bottom black bars. I took a bmp of a frame and put it into Photoshop and it shows that the image size is indeed 787x432. I cropped out the black bars and the image now shows as 787x332 (which is 2.37).

I put this avi into VirtualDubMod and cropped the bars. I ended up with a 780x332 (2.35) video and the avi plays full widescreen on my PC monitor with no bars.

So I'd like to know is, how does one determine at what aspect ratio a rip should be?

[Ghitulescu]

16:9 WS means that a wide screen image is anamorph resized to 720x576 (x480) pixels. A pure 16:9 image will have no black bars (matting).
2.35:1 letterbox means that inside that 16:9 image, only 2.35 is actually image, the rest being the mattes.
A 2.35:1 inside a 4:3LB would have huge mattings (more than half of the image).

I'll put some images soon...

[peppi_le_piou]

Thanks, how does all this affect ripping to avi. Will it always have matting?

[Ghitulescu]

Some images from various movies, to see how easy is to automatisate this ;)

La vingtcinquième heure, 16:9 anamorph, 2.35:1 real image, overscan
http://oi56.tinypic.com/hx4rb7.jpg
The unbearabale lightness of being, 16:9 anamorph, no overscan
http://oi51.tinypic.com/ndsflw.jpg
Discovery channel, 43LB, overscan
http://oi51.tinypic.com/m7dg12.jpg
From Hell, 16:9, 2.35:1, no overscan
http://oi55.tinypic.com/2u94xti.jpg
Hamilton, 16:9 anamorph, overscan
http://oi52.tinypic.com/25ahpat.jpg
The hawaiians, 4:3LB, 2.35:1 real image, no overscan
http://oi56.tinypic.com/oid93b.jpg

[Ghitulescu]

For the sake of simplification, all "real image" DARs were noted as 2.35:1, overscan meant that the analog TV overscan was considered (all info visible). All images from PAL DVDs.

[hopstiii]

I take snapshot from VLC of DVD
http://static3.nagi.ee/i/p/725/13/1812841902c2f3_o.jpg

It was 1024x576,
There are vertical and horizontal black bars - i crop.
Then i see what might the output resolution to be - it's 1024x432.
And then i crop and resample from 720x576 to correct resolution keeping in mind not loosing vertical resolution
but up resampling the horizontal 720 to 1024 (pixel is square).
Also that might brake res standards if DXVA compatible x264 is the idea.

Old XviD Rip @ 2121 Kbps
http://static3.nagi.ee/i/p/725/13/18128417b955f5_m.jpg (http://static3.nagi.ee/i/p/725/13/18128417b955f5_o.jpg)

[Ghitulescu]

Of course it was simple, because you had the picture in front of you :) and used your brain. Imagine you're blind and you have a framed picture with a passepartout (a white/beige/black border around). How can you tell where the real image ends? You can't. So is the computer. It has to be told each time all these details.
And of course 1024 = 576 * 16 / 9 (the very same way 768 = 576 * 4 / 3).
But how much should one crop from the left, right, top and bottom? Now think of movies that have a variable overscan (some scenes have borders, some don't). Isn't fun converting movies? :)

[hopstiii]

Didn't DVDFab had some automated process for that?
http://www.dvdfab8.com/dvd-ripper.htm

[J_Darnley]

There is also an avisynth plugin which tries to do the same, but as with most things on a computer, it is not smart.

[peppi_le_piou]

IMDB film details shows that most film is shot in 2.35:1 aspect and dvd releases are 16:9, so therefore will all dvd rips (backups of course) contain matting? And if matts are not wanted then they are cropped which will in most cases result in a 2.35:1 picture.

[hopstiii]

Beerfest (2006) was just cropped to wide from 4/3.
Some scenes are totally ruined like cointricks not showing total pathway of coin throwing.

[peppi_le_piou]

Before you cropped it how did it look on playback? ie with the automatic black matts that are there. Was the coin scene good?

[Ghitulescu]

Beerfest (2006) was just cropped to wide from 4/3.
Some scenes are totally ruined like cointricks not showing total pathway of coin throwing.

Almost all movies are cropped from 4:3 (except those with anamorph lenses, mostly spaghetti western and peplums). It's the director the one who's responsible for framing the scenes during shoting to allow a better cut. Funny enough, most 4:3 movies are sold as B-price in undeveloped countries, although some of them are in fact PS (pan&scan) versions and not FS (full screen) ones, so be careful.

[hopstiii]

Before you cropped it how did it look on playback? ie with the automatic black matts that are there. Was the coin scene good?

I didn't crop but there was at least 2 DVD versions of that movie.
One wide 16:9 - 2.35:1 Wide link (http://www.amazon.co.uk/Beerfest-DVD-Region-US-NTSC/dp/B000JJ4DNW/ref=sr_1_2?ie=UTF8&s=music&qid=1303371063&sr=8-2)
and one 4:3 - 1.33:1 4/3 Link (http://www.amazon.co.uk/Beerfest-DVD-Region-US-NTSC/dp/B000JJ4DO6/ref=sr_1_fkmr1_1?ie=UTF8&qid=1303370938&sr=8-1-fkmr1)

The 4/3 had wider vertical and diagonal camera view angle or field of view. Therefor much better scene coverage.
----

Most times i don't see on DVD box if it's PS (pan&scan) or FS (full screen)

[peppi_le_piou]

So what do you guys do with your rips. Do you crop it to the actual film image (most times 2.35:1) or rip it to the dvd released format 16:9 with black matt.

[hopstiii]

I have cropped black matt away.
But lately i have discovered DXVA and it resolution AR requirement to run in MPC-HC hardware accelerated mode.
+ the solid black large area doesn't take andy size in file.

[peppi_le_piou]

IMDB shows that a movie was shot at 1.85:1 and that means a resolution of say 848x464 (to stay within multiples of 16).

Yet 16:9 is 1.78, so what happens here. Why don't they make the film in 1.78

[netmask]

IMDB shows t snip

Yet 16:9 is 1.78, so what happens here. Why don't they make the film in 1.78

Because directors like a particular aspect ratio and they are making films for the cinema - directors like Kubreck and Hitchcock had there own idiosyncratic ideas of how they would shoot the film and then crop for public release much the same as a painter will choose the canvas size and not some convenient size that fits into an average living room....

When I rip movies for viewing on my 16:9 screen I don't crop I like to see black bars if it is a 2.35:1 movie - I much prefer to see movies in their actual AR. I can always sit closer if need be. Visit the Widescreen Museum for a definitive history of cinema aspect ratios over the years.
http://www.widescreenmuseum.com/index.htm#main%20index

With modern blockbusters it is fairly routine now to release both an original AR and a cropped version in 16:9. The cinematographer frames the important action in the central area in such a way that side cropping doesn't impinge too much on the action.

With 1.85 it was designed to be cropped in the cinema for a "wider" presentation if the manager wanted to do so

[hopstiii]

that means a resolution of say 848x464 (to stay within multiples of 16).

I know multiples of 4 to 16 was needed for XviD GMC feature.
Or am i wrong.

Anyways x264 can have merange 64, but do i need to have it like that:

merange 40
1280/40 = 32
720/40 = 18

Is there problem with
1280/64 = 20
720/64 = 11,25

or 1280 x 768
because 768 is divisible by 64

[J_Darnley]

x264 has no size requirements like that. Any merange larger than the default of 16 is pointless. Even placebo only uses 24.

[peppi_le_piou]

I don't have a widescreen tv yet so I can't try these myself.

If I have a dvd with DAR of 1.778 then should I rip it to 1.85 (800x432) or 1.75 (784x448). How would these look played back on a widescreen tv? Which resolution is preferrable?

[edit] or maybe 784x432 (1.81) it's closer to the original.

[Ghitulescu]

How would these look played back on a widescreen tv?
It depends on many factors.
Which resolution is preferrable?
As you probably learned from my snapshots, there's no "automatic" answer if one wants to get rid of all black borders. Then there's the 16pix requirement of MPEG algorithm, then the change of PAR ....